1. Field of the Invention
The present invention relates to a method of inspecting a substrate processing apparatus and a storage medium storing an inspection program for executing the method, and more particularly to a method of inspecting a substrate processing apparatus using a substrate conveyed therein.
2. Description of the Related Art
A substrate processing apparatus for performing predetermined processing on substrates is comprised of a plurality of processing units (substrate processing chambers) as vacuum processing chambers, a load-lock chamber as a conveying chamber which is connected to the processing units and whose internal pressure is switched between vacuum and atmospheric pressure, a carrier-mounting stage on which carrier boxes containing a plurality of substrates are placed, and a loader unit as a conveying chamber which is disposed between the load-lock chamber and the carrier-mounting stage and whose internal pressure is set to atmospheric pressure.
In the substrate processing apparatus, a substrate is conveyed from one of the carrier boxes to one of the processing units via the loader unit and the load-lock chamber, and subjected to plasma processing, such as etching, in the processing unit. In this case, when particles are deposited on the substrate or when the etching rate in the processing falls outside a predetermined range, the manufacturing yield of semiconductor devices made of the substrates is degraded.
The amount of particles deposited on each substrate and the etching rate change depending on the condition of the substrate processing apparatus, especially the condition of the processing unit as a component thereof, and therefore in the substrate processing apparatus, it is necessary to inspect the condition of each processing unit periodically.
Conventionally, to inspect the condition of the processing unit periodically, there has been employed a method of investigating the inside of the processing unit by opening the lid thereof. According to this method, however, it takes time to reproduce a vacuum in the processing unit after inspection, which makes it impossible to inspect the processing unit frequently.
To solve this problem, there has recently been developed a method of inspecting the condition of the processing unit by conveying an inspection substrate different from product substrates into the substrate processing apparatus for etching, and measuring the amount of particles deposited on the etched inspection substrate and the etching rate. This method makes it unnecessary to open the lid of the processing unit, and hence makes it possible to inspect the processing unit frequently.
As the method using the inspection substrate, there have been proposed a method in which the operator designates a processing unit to be inspected, whereafter a carrier box containing the inspection substrate is placed on the carrier-mounting stage, and the inspection substrate is conveyed into the processing unit to be inspected, for processing the inspection substrate, and a method in which the operator inserts the inspection substrate into a sorter storing product substrates according to a process procedure stored in advance in the apparatus, whereafter the inspection substrate is conveyed into the processing apparatus, for being processed (see e.g. the publication of Japanese Patent No. 2730538).
However, in the method in which the operator designates a processing unit to be inspected, the operator alone can determine the type of substrate supplied to the processing unit to be inspected, and hence if the operator is not aware that the processing unit to which he/she is about to supply the substrate is a processing unit to be inspected, he can erroneously supply a product substrate into the processing unit to be inspected.
Further, in the method making use of the process procedure stored in advance in the apparatus, the inspection substrate is inserted into the sorter according to the process procedure and further conveyed into the processing apparatus. Therefore, there is no fear that product substrates are erroneously supplied, but the operator is required to prepare the process procedure in advance, which makes it impossible to inspect the condition of a processing unit in desired timing.